70.爬楼梯.md

爬楼梯

解题思路

动态规划

f(n) = f(n - 1) + f(n - 2)

f(0) = 1 f(1) = 1 f(2) = f(1) + f(0) = 2 f(3) = f(2) + f(1) = 3

function climbStairs(n: number): number {
    let r = 1 // n
    let p = 0 // n - 1
    let q = 0 // n - 2
    for (let i = 1; i <= n; i++) {
        q = p
        p = r
        r = p + q
    }
    return r
};